Zwitterion-Modified PMMA Interlayers for Reliable Dual-Mode Organic Neuromorphic Devices

Organic electrochemical transistors (OECTs) and electrolyte-gated organic field-effect transistors (EGOFETs) represent promising technologies for neuromorphic computing. Yet, conventional dual-mode devices suffer from fundamental performance trade-offs, where optimization for one mode compromises the other. The primary challenge stems from incompatible interfacial requirements: EGOFETs require stable polarization layers preventing ion penetration, while OECTs demand efficient ionic transport for volumetric doping. Here, we present a novel materials engineering strategy employing zwitterionic-modified poly(methyl methacrylate) (PMMA-ZI) as an interlayer to address this fundamental incompatibility. The amphiphilic zwitterionic moieties simultaneously enhance dipolar polarization for EGOFET operation and facilitate balanced ion transport for OECT functionality through controlled electrostatic interactions. PMMA-ZI devices demonstrate remarkable performance enhancements, with a 13.57-fold improvement in the volumetric capacitance-mobility product to 57.25 F cm^-1 V^-1 s^-1 in OECT mode, compared to conventional PMMA interlayers. The devices exhibit exceptional synaptic plasticity with 6.12 times improved memory retention and successful implementation of 4-bit reservoir computing for pattern recognition. This work establishes a new paradigm for dual-mode organic transistors, enabling uncompromised multifunctional operation essential for next-generation neuromorphic computing and bioelectronics applications.